1. Field of the Invention
The present invention relates to a choke coil, and more particularly to a choke coil which eliminates noise leaking out of an electronic appliance.
2. Description of Related Art
A conventional common mode choke coil has a structure wherein a couple of coils are wound around a circular core. In eliminating strong differential mode noise by use of this type of common mode choke coil, a large-sized choke coil is required, and the choke coil occupies a large area of a printed circuit board.
A choke coil disclosed by Japanese Patent Laid Open Publication No. 4-91412 is very effective to eliminate differential mode noise and common mode noise. However, this choke coil has a structure wherein three circular cores are linked, and this is unsatisfactory with respect to size and cost.